Westward expansion helped define the American experience in the 19th century. The United States extended from coast-to-coast, with the largest acquisition being the Louisiana Purchase (1803). New transportation technology, such as canals and railroads, and settlement acts like the 1862 Homestead Act helped spur settlement. Thousands of people left the eastern half of the continent looking for better opportunities in the west. Sitting in the middle of all of this movement was Nebraska and thousands of people settled there to form agricultural communities with the land they acquired from the government's land holdings.

With the Kansas-Nebraska Act of 1854, Congress created the Kansas and Nebraska territories out of land acquired under the Louisiana Purchase. This bill overturned the Missouri Compromise of 1820, which had banned slavery in new territories in the north. The Kansas-Nebraska Act allowed the people of each new territory to decide whether they would allow slavery or not. After experiencing bloody disputes over slavery, Kansas became a free state in 1861. The initial boundaries of the Nebraska Territory encompassed much more land than today's borders. But by 1864, parcels of land had been taken away, leaving the borders of Nebraska similar to that of today. By that time, it was clear that Nebraska had firmly entered the road to statehood.

The United States Congress gave Nebraskans the authority to draft a state constitution in 1864, but none was drafted. In 1866, two years after the enabling legislation, a constitution drafted by the legislature was narrowly ratified and sent to the President and Congress for approval. Because Congress required the Nebraska state constitution be changed to allow black men the right to vote, President Andrew Johnson vetoed the statehood bill. He believed that Congress had no right to dictate to states provisions of their constitutions. Congress overrode the veto and Nebraska entered the Union as the 37th state on March 1, 1867.